1. Field of the Invention
This invention relates, generally, to the art of concrete, asphalt, and other aggregate construction. More particularly, it relates to devices for holding the forms used in such construction.
2. Description of the Prior Art
Concrete construction requires that boards, generally called "forms" in the industry, be joined end to end along the inside and outside borders of the walk, ramp, headwall, pad, or other structure to be formed. Construction projects including asphalt or other aggregates also require the use of such forms in some applications.
The conventional means for joining forms includes the steps of manually aligning a pair of boards in end to end relation to one another and nailing a short board, known as a "scab," to an outside surface thereof; the scab bridges the parting line where the two boards or forms meet. After the concrete or other aggregate has been poured and allowed to cure, the nails are removed so that the scab and the forms can be reused.
There are a number of drawbacks associated with the presently used technique. First of all, the process of nailing a scab into position is time-consuming, as is the process of removing the nails when the aggregate has cured. Moreover, the scabs are quickly destroyed by the repeated nailings, as are the abutting ends of the forms. This wearing out of scabs and forms is now dealt with by frequent discarding of scabs and frequent trimming of the forms, i.e., the ends of the forms are cut off so that the remaining length thereof can be reused; obviously, the forms become shorter with each trimming and they soon become too short for their intended use.
The quick deterioration of wooden scabs and forms led inventors to develop metallic frames that could supplant the use of their wooden counterparts. Although the metallic devices are durable, they have their own set of shortcomings that limit their utility. For example, metallic forms are manufactured in just a few commonly used lengths such as ten feet, twelve feet, and the like. Thus, they have no utility in applications calling for nonstandard lengths. Moreover, such forms are quite heavy, and sometimes contribute to back injuries. Since damage claims often lead to substantial workmen's compensation expenses, many cities and private contractors are reluctant to use metallic frames. Accordingly, light-in-weight wooden forms continue to be the materials of choice, even though they cannot be installed as quickly as metallic forms and even though they do not last as long.
Ramp construction is also problematic. The Americans with Disabilities Act requires that sidewalks include wheelchair ramps at all curbs or other stepped places. That law currently requires that the slope of ramps may not exceed five degrees; where wooden forms and scabs are employed, measurement of such a slope is a time-consuming project.
Another problem in the industry is the need to build sidewalks, curbs, and the like in uniform widths. For example, a city ordinance might require that all sidewalks have a uniform minimum width of four feet and that all curbs have a certain minimum uniform width. The conventional compliance procedure for meeting these requirements is to measure the width of each section of the structure as the forms are placed into position. One obvious shortcoming of this procedure is that mismeasurements will be made and sections of the completed structure will have to be destroyed and rebuilt; another obvious shortcoming is the time-intensive nature of the procedure.
Thus, what is needed is a new way to join forms in end-to-end relation to one another in the absence of scabs. The new way would lengthen the usable lifetime of the forms, would eliminate the wasteful use of scabs, and would shorten the time required to complete a form installation. New ways to provide ramps and to place forms into parallel relation to one another at a fixed predetermined distance are also required.
At the time the present invention was made, however, it was not obvious to those of ordinary skill in this art how these desireable objectives could be obtained, in view of the prior art when considered as a whole.